A genteel disquisition on love and lust in the animal kingdom
Basic Instincts
Obviously, scientific accuracy is important. But did a zoo’s web-
site have to upend a beloved Christmas folktale by publishing
this sentence: “Rudolph the red-nosed reindeer must have
been a female”?
Now, now. Compose yourselves. This all can be explained.
Rangifer tarandus includes the caribou of North America
and the reindeer of Eurasia. Reproductive biologist Peter Flood
of the University of Saskatchewan, Canada, says it is the only
deer species in which both sexes grow antlers—and in which
annual rack-shedding cycles separate the bulls from the cows.
In spring both sexes begin to grow antlers that, by fall, harden
to bone. Flood says adult males’ antlers are rightly called weap-
ons of sex, used to drive off other bulls in rut. Once the cows are
pregnant, adult bulls’ testosterone levels drop, triggering a bone
cell change that makes their antlers fall off, usually in Novem-
ber or December. Young males keep their antlers somewhat
longer—but pregnant cows keep their racks all winter and into
spring, the better to fend off threats and guard feeding sites.
Only after they give birth, typically in April or May, do they shed
their antlers (which nonpregnant cows did some weeks earlier).
So to give Santa’s sleigh pullers their due, let us clarify.
Reindeer still antlered on Christmas Eve may be adolescent
males—but could very well be females, and pregnant ones at
that.
—Patricia Edmonds
HABITAT/RANGE
Tundra and taiga zones of
Eurasia and North America
CONSERVATION STATUS
Least concern
OTHER FACTS
Climate warming in Rangifer
tarandus’s range causes
more melting and re-icing
of snow, making it harder
for them to dig for food.
Her Rack Versus His
This female reindeer was photographed at
the Miller Park Zoo, Bloomington, Illinois.